;
; - page 0 is top line, page 7 ist bottom line
; - column 0 is the leftmost colum, column 127 is the rightmost column
; - a page has a height of 8 (->8 bits)
; - when writing a byte to a position (e.g. page 0, column 0)
; - writing to chip RAM is done in columns
;
; Page 0:    col 0 col 1 ... col 127
; Row 0(LSB) 0/0   1/0   ... 127/0
; Row 1      0/1   1/1   ... 127/1
; Row 2      0/2   1/2   ... 127/2
; Row 3      0/3   1/3   ... 127/3
; ...
; Row 7(MSB) 0/7   1/7   ... 127/7
; and so one


; ***************************************************************************
; defines

.equ LCD_CONTROLBYTE_DC_MASK = 0x40
.equ LCD_CONTROLBYTE_CO_MASK = 0x80

.equ LCD_TWI_ADDRESS         = 0x3c

.equ LCD_WIDTH               = 128
.equ LCD_HEIGHT              = 64

.equ LCD_PAGE_COUNT          = 8
.equ LCD_MULTIPLE            = 2
.equ LCD_CMD_MODE            = 0x00
.equ LCD_DATA_MODE           = 0x40



; ***************************************************************************
; data

.dseg

lcdDataBegin:
lcdDataEnd:



; ***************************************************************************
; code

.cseg




LCD_Init:
 sbi DDRA, PORTA2 ; debug
 sbi PORTA, PORTA2 ; debug (off)

  ldi zl, LOW(lcdInitCommandsBegin)
  ldi zh, HIGH(lcdInitCommandsBegin)
  ldi r16, 8
  rcall lcdWriteCommandsFromFlash

  ldi r16, 0
  rcall LCD_Fill

  ldi r16, 255
  rcall LCD_Fill

  ldi r16, 0
  rcall LCD_Fill

  ldi r18, 0
  ldi r19, 0
  rcall LCD_SetCursor

  ldi zl, LOW(lcdHelloMsg1)
  ldi zh, HIGH(lcdHelloMsg1)
  rcall LCD_PrintFromFlash

  ldi r18, 0
  ldi r19, 2
  rcall LCD_SetCursor

  ldi zl, LOW(lcdHelloMsg2)
  ldi zh, HIGH(lcdHelloMsg2)
  rcall LCD_PrintFromFlash

  ldi r18, 0
  ldi r19, 4
  rcall LCD_SetCursor

  ldi zl, LOW(lcdHelloMsg3)
  ldi zh, HIGH(lcdHelloMsg3)
  rcall LCD_PrintFromFlash

  ldi r18, 10
  ldi r19, 5
  rcall LCD_SetCursor

  ldi zl, LOW(lcdHelloMsg4)
  ldi zh, HIGH(lcdHelloMsg4)
  rcall LCD_PrintFromFlash


  sec
  ret




; - R16: number of bytes to send
; - Z=pointer to data
lcdWriteCommandsFromFlash:
  rcall twiStart
  lsl zl
  rol zh
  mov r20, r16   ; number of bytes
  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByte
  brcc lcdWriteCommandsFromFlash_error
  tst r16
  brne lcdWriteCommandsFromFlash_error
  
lcdWriteCommandsFromFlash_loop:
    lpm r16, z+
    rcall twiSendByte
    brcc lcdWriteCommandsFromFlash_error
    tst r16
    brne lcdWriteCommandsFromFlash_error
    dec r20
  brne lcdWriteCommandsFromFlash_loop
  rcall twiStop
 sbi DDRA, PORTA2 ; debug
 cbi PORTA, PORTA2 ; debug (on)
  sec
  ret

lcdWriteCommandsFromFlash_error:
  rcall twiStop
  clc
  ret



; ---------------------------------------------------------------------------
; LCD_SetCursor
;
; Set cursor.
;
; IN:
; - R18: X
; - R19: Y
; OUT:
; - nothing
; REGS: r1, r2, r16 (R16, R17, R18, R22)

LCD_SetCursor:
  mov r1, r18
  mov r2, r19
  rcall twiStart             ; (R22)
  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_SetCursor_error

  ldi r16, LCD_CMD_MODE
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_SetCursor_error
  mov r16, r2
  andi r16, 0x07
  ori r16, 0xb0
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_SetCursor_error
  mov r16, r1
  andi r16, 0x0f
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_SetCursor_error
  mov r16, r1
  andi r16, 0xf0
  swap r16
  ori r16, 0x10
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_SetCursor_error

  rcall twiStop              ; (R22)
  sec
  ret
LCD_SetCursor_error:
  rcall twiStop              ; (R22)
  clc
  ret



; - R16: data to write
LCD_Fill:
  mov r20, r16

  ldi r21, 0 ; Y
LCD_Fill_loopY:
    clr r18
    mov r19, r21
    rcall LCD_SetCursor
    brcc LCD_Fill_error

    rcall twiStart
    ldi r16, (LCD_TWI_ADDRESS*2)
    rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
    brcc LCD_Fill_error
    ldi r16, LCD_DATA_MODE
    rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
    brcc LCD_Fill_error
  
    ldi r19, 0
LCD_Fill_loopX:
      mov r16, r20
      rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
      rcall twiSendByte
      brcc LCD_Fill_error
      inc r19
      cpi r19, LCD_WIDTH
    brcs LCD_Fill_loopX
    rcall twiStop
    inc r21
    cpi r21, LCD_PAGE_COUNT
  brcs LCD_Fill_loopY
  sec
  ret
LCD_Fill_error:
  rcall twiStop
  clc
  ret


; ---------------------------------------------------------------------------
; LCD_PrintFromFlash
;
; Print a string from flash at the current position.
;
; IN:
; - Z: position of string to print
; OUT:
; - CFLAG: set if okay, cleared otherwise
; REGS: 
LCD_PrintFromFlash:
  lsl zl
  rol zh
  rcall twiStart
  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_PrintFromFlash_error
  ldi r16, LCD_DATA_MODE
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_PrintFromFlash_error

LCD_PrintFromFlash_loop:
    lpm r16, z+
    tst r16
    breq LCD_PrintFromFlash_end
    push zh
      push zl
        rcall lcdPrintOneChar
      pop zl
    pop zh
    brcc LCD_PrintFromFlash_error
  rjmp LCD_PrintFromFlash_loop
LCD_PrintFromFlash_end:
  rcall twiStop
  sec
  ret
  
LCD_PrintFromFlash_error:
  rcall twiStop
  clc
  ret



; ---------------------------------------------------------------------------
; LCD_PrintChar
;
; Print a character at the current position.
;
; IN:
; - R16: char
; OUT:
; REGS: r16, r17, Z
LCD_PrintChar:
  rcall twiStart
  ldi r16, (LCD_TWI_ADDRESS*2)
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_PrintChar_error
  ldi r16, LCD_DATA_MODE
  rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
  brcc LCD_PrintChar_error

  rcall lcdPrintOneChar
  brcc LCD_PrintChar_error
  rcall twiStop
  sec
  ret
  
LCD_PrintChar_error:
  rcall twiStop
  clc
  ret



; ---------------------------------------------------------------------------
; lcdPrintOneChar
;
; Print a character at the current position.
;
; IN:
; - R16: char
; OUT:
; REGS: r16, r17, Z

lcdPrintOneChar:
  rcall lcdGetCharMatrix
  ldi r16, 0                   ; spacing between chars
  rcall twiSendByteExpectAck   ; (R16, R17, R18, R22)
  brcc lcdPrintOneChar_error
  ldi r19, 6
lcdPrintOneChar_loop:
    lpm r16, z+
    rcall twiSendByteExpectAck ; (R16, R17, R18, R22)
    brcc lcdPrintOneChar_error
    dec r19
  brne lcdPrintOneChar_loop
  sec
  ret
  
lcdPrintOneChar_error:
  clc
  ret


; ---------------------------------------------------------------------------
; lcdGetCharMatrix
;
; Get pointer to matrix of given char.
;
; IN:
; - R16: char
; OUT:
; - Z: pos of character matrix (ready for LPM)
; REGS: r16, r17, Z
lcdGetCharMatrix:
  cpi r16, 95+32
  brcc lcdGetCharMatrix_l1
  cpi r16, 32
  brcc lcdGetCharMatrix_l2
lcdGetCharMatrix_l1:
  ldi r16, 32
lcdGetCharMatrix_l2:
  ldi r17, 32
  sub r16, r17
  mov zl, r16
  clr zh
  clr r17
  lsl zl      ; *2
  rol zh
  add zl, r16 ; *3
  adc zh, r17
  lsl zl      ; *6
  rol zh
  ldi r16, LOW(lcdFont6x8*2)
  ldi r17, HIGH(lcdFont6x8*2)
  add zl, r16
  adc zh, r17
  ret



lcdInitCommandsBegin:  ; 28 bytes
   .db LCD_CMD_MODE, 0xa8, ((LCD_PAGE_COUNT*8)-1), 0x8d, 0x14, 0xaf, 0xa1, 0xc8
lcdInitCommandsEnd:
  .db 0xae, 0x00, 0x10, 0x40, 0x81, 0xcf, 0xa1, 0xc8
  .db 0xa6, 0xa8, 0x3f, 0xd3, 0x00, 0xd5, 0x80, 0xd9
  .db 0xf1, 0xda, 0x12, 0xdb, 0x40, 0x20, 0x02, 0x8d
  .db 0x14, 0xa4, 0xa6, 0xaf

lcdHelloMsg1: .db "ILD :-)", 0
;lcdHelloMsg2: .db "1234567890ABCDEFGH", 0, 0
lcdHelloMsg2: .db "ICH LIEBE DICH!", 0
lcdHelloMsg3: .db "abcdefghijklmnopqr", 0, 0
lcdHelloMsg4: .db "abcde", 0

lcdFont6x8:
  .db 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ;   0 
  .db 0x00, 0x00, 0x00, 0x2f, 0x00, 0x00 ; ! 1 
  .db 0x00, 0x00, 0x07, 0x00, 0x07, 0x00 ; " 2 
  .db 0x00, 0x14, 0x7f, 0x14, 0x7f, 0x14 ; # 3 
  .db 0x00, 0x24, 0x2a, 0x7f, 0x2a, 0x12 ; $ 4 
  .db 0x00, 0x62, 0x64, 0x08, 0x13, 0x23 ; % 5 
  .db 0x00, 0x36, 0x49, 0x55, 0x22, 0x50 ; & 6 
  .db 0x00, 0x00, 0x05, 0x03, 0x00, 0x00 ; ' 7 
  .db 0x00, 0x00, 0x1c, 0x22, 0x41, 0x00 ; ( 8 
  .db 0x00, 0x00, 0x41, 0x22, 0x1c, 0x00 ; ) 9 
  .db 0x00, 0x14, 0x08, 0x3E, 0x08, 0x14 ; * 10
  .db 0x00, 0x08, 0x08, 0x3E, 0x08, 0x08 ; + 11
  .db 0x00, 0x00, 0x00, 0xA0, 0x60, 0x00 ; , 12
  .db 0x00, 0x08, 0x08, 0x08, 0x08, 0x08 ; - 13
  .db 0x00, 0x00, 0x60, 0x60, 0x00, 0x00 ; . 14
  .db 0x00, 0x20, 0x10, 0x08, 0x04, 0x02 ; / 15
  .db 0x00, 0x3E, 0x51, 0x49, 0x45, 0x3E ; 0 16
  .db 0x00, 0x00, 0x42, 0x7F, 0x40, 0x00 ; 1 17
  .db 0x00, 0x42, 0x61, 0x51, 0x49, 0x46 ; 2 18
  .db 0x00, 0x21, 0x41, 0x45, 0x4B, 0x31 ; 3 19
  .db 0x00, 0x18, 0x14, 0x12, 0x7F, 0x10 ; 4 20
  .db 0x00, 0x27, 0x45, 0x45, 0x45, 0x39 ; 5 21
  .db 0x00, 0x3C, 0x4A, 0x49, 0x49, 0x30 ; 6 22
  .db 0x00, 0x01, 0x71, 0x09, 0x05, 0x03 ; 7 23
  .db 0x00, 0x36, 0x49, 0x49, 0x49, 0x36 ; 8 24
  .db 0x00, 0x06, 0x49, 0x49, 0x29, 0x1E ; 9 25
  .db 0x00, 0x00, 0x36, 0x36, 0x00, 0x00 ; : 26
  .db 0x00, 0x00, 0x56, 0x36, 0x00, 0x00 ; ; 27
  .db 0x00, 0x08, 0x14, 0x22, 0x41, 0x00 ; < 28
  .db 0x00, 0x14, 0x14, 0x14, 0x14, 0x14 ; = 29
  .db 0x00, 0x00, 0x41, 0x22, 0x14, 0x08 ; > 30
  .db 0x00, 0x02, 0x01, 0x51, 0x09, 0x06 ; ? 31
  .db 0x00, 0x32, 0x49, 0x59, 0x51, 0x3E ; @ 32
  .db 0x00, 0x7C, 0x12, 0x11, 0x12, 0x7C ; A 33
  .db 0x00, 0x7F, 0x49, 0x49, 0x49, 0x36 ; B 34
  .db 0x00, 0x3E, 0x41, 0x41, 0x41, 0x22 ; C 35
  .db 0x00, 0x7F, 0x41, 0x41, 0x22, 0x1C ; D 36
  .db 0x00, 0x7F, 0x49, 0x49, 0x49, 0x41 ; E 37
  .db 0x00, 0x7F, 0x09, 0x09, 0x09, 0x01 ; F 38
  .db 0x00, 0x3E, 0x41, 0x49, 0x49, 0x7A ; G 39
  .db 0x00, 0x7F, 0x08, 0x08, 0x08, 0x7F ; H 40
  .db 0x00, 0x00, 0x41, 0x7F, 0x41, 0x00 ; I 41
  .db 0x00, 0x20, 0x40, 0x41, 0x3F, 0x01 ; J 42
  .db 0x00, 0x7F, 0x08, 0x14, 0x22, 0x41 ; K 43
  .db 0x00, 0x7F, 0x40, 0x40, 0x40, 0x40 ; L 44
  .db 0x00, 0x7F, 0x02, 0x0C, 0x02, 0x7F ; M 45
  .db 0x00, 0x7F, 0x04, 0x08, 0x10, 0x7F ; N 46
  .db 0x00, 0x3E, 0x41, 0x41, 0x41, 0x3E ; O 47
  .db 0x00, 0x7F, 0x09, 0x09, 0x09, 0x06 ; P 48
  .db 0x00, 0x3E, 0x41, 0x51, 0x21, 0x5E ; Q 49
  .db 0x00, 0x7F, 0x09, 0x19, 0x29, 0x46 ; R 50
  .db 0x00, 0x46, 0x49, 0x49, 0x49, 0x31 ; S 51
  .db 0x00, 0x01, 0x01, 0x7F, 0x01, 0x01 ; T 52
  .db 0x00, 0x3F, 0x40, 0x40, 0x40, 0x3F ; U 53
  .db 0x00, 0x1F, 0x20, 0x40, 0x20, 0x1F ; V 54
  .db 0x00, 0x3F, 0x40, 0x38, 0x40, 0x3F ; W 55
  .db 0x00, 0x63, 0x14, 0x08, 0x14, 0x63 ; X 56
  .db 0x00, 0x07, 0x08, 0x70, 0x08, 0x07 ; Y 57
  .db 0x00, 0x61, 0x51, 0x49, 0x45, 0x43 ; Z 58
  .db 0x00, 0x00, 0x7F, 0x41, 0x41, 0x00 ; [ 59
  .db 0x00, 0x02, 0x04, 0x08, 0x10, 0x20 ; \ 60
  .db 0x00, 0x00, 0x41, 0x41, 0x7F, 0x00 ; ] 61
  .db 0x00, 0x04, 0x02, 0x01, 0x02, 0x04 ; ^ 62
  .db 0x00, 0x40, 0x40, 0x40, 0x40, 0x40 ; _ 63
  .db 0x00, 0x00, 0x01, 0x02, 0x04, 0x00 ; ' 64
  .db 0x00, 0x20, 0x54, 0x54, 0x54, 0x78 ; a 65
  .db 0x00, 0x7F, 0x48, 0x44, 0x44, 0x38 ; b 66
  .db 0x00, 0x38, 0x44, 0x44, 0x44, 0x20 ; c 67
  .db 0x00, 0x38, 0x44, 0x44, 0x48, 0x7F ; d 68
  .db 0x00, 0x38, 0x54, 0x54, 0x54, 0x18 ; e 69
  .db 0x00, 0x08, 0x7E, 0x09, 0x01, 0x02 ; f 70
  .db 0x00, 0x18, 0xA4, 0xA4, 0xA4, 0x7C ; g 71
  .db 0x00, 0x7F, 0x08, 0x04, 0x04, 0x78 ; h 72
  .db 0x00, 0x00, 0x44, 0x7D, 0x40, 0x00 ; i 73
  .db 0x00, 0x40, 0x80, 0x84, 0x7D, 0x00 ; j 74
  .db 0x00, 0x7F, 0x10, 0x28, 0x44, 0x00 ; k 75
  .db 0x00, 0x00, 0x41, 0x7F, 0x40, 0x00 ; l 76
  .db 0x00, 0x7C, 0x04, 0x18, 0x04, 0x78 ; m 77
  .db 0x00, 0x7C, 0x08, 0x04, 0x04, 0x78 ; n 78
  .db 0x00, 0x38, 0x44, 0x44, 0x44, 0x38 ; o 79
  .db 0x00, 0xFC, 0x24, 0x24, 0x24, 0x18 ; p 80
  .db 0x00, 0x18, 0x24, 0x24, 0x18, 0xFC ; q 81
  .db 0x00, 0x7C, 0x08, 0x04, 0x04, 0x08 ; r 82
  .db 0x00, 0x48, 0x54, 0x54, 0x54, 0x20 ; s 83
  .db 0x00, 0x04, 0x3F, 0x44, 0x40, 0x20 ; t 84
  .db 0x00, 0x3C, 0x40, 0x40, 0x20, 0x7C ; u 85
  .db 0x00, 0x1C, 0x20, 0x40, 0x20, 0x1C ; v 86
  .db 0x00, 0x3C, 0x40, 0x30, 0x40, 0x3C ; w 87
  .db 0x00, 0x44, 0x28, 0x10, 0x28, 0x44 ; x 88
  .db 0x00, 0x1C, 0xA0, 0xA0, 0xA0, 0x7C ; y 89
  .db 0x00, 0x44, 0x64, 0x54, 0x4C, 0x44 ; z 90
  .db 0x00, 0x08, 0x36, 0x41, 0x41, 0x00 ; { 91
  .db 0x00, 0x00, 0x00, 0x7F, 0x00, 0x00 ; | 92
  .db 0x00, 0x00, 0x41, 0x41, 0x36, 0x08 ; } 93
  .db 0x00, 0x08, 0x04, 0x08, 0x10, 0x08 ; ~ 94